Imprint lithography

ABSTRACT

An imprinting method is disclosed that, in embodiment, includes contacting first and second spaced target regions of an imprintable medium on a substrate with first and second templates respectively to form respective first and second imprints in the medium and separating the first and second templates from the imprinted medium.

FIELD

The present invention relates to imprint lithography.

BACKGROUND

A lithographic apparatus is a machine that applies a desired patternonto a target portion of a substrate. Lithographic apparatus areconventionally used, for example, in the manufacture of integratedcircuits (ICs), flat panel displays and other devices involving finestructures.

It is desirable to reduce the size of features in a lithographic patternbecause this allows for a greater density of features on a givensubstrate area. In photolithography, the increased resolution may beachieved by using radiation of a short wavelength. However, there areproblems associated with such reductions. Lithographic apparatus using193 nm wavelength radiation are starting to be adopted but even at thislevel, diffraction limitations may become a barrier. At lowerwavelengths, the transparency of projection system materials is poor.Thus, optical lithography capable of enhanced resolution will likelyrequire complex optics and rare materials and thus will be expensive.

An alternative method to printing sub-100 nm features, known as imprintlithography, comprises transferring a pattern to a substrate byimprinting a pattern into an imprintable medium using a physical mouldor template. The imprintable medium may be the substrate or a materialcoated onto a surface of the substrate. The imprintable medium may befunctional or may be used as a “mask” to transfer a pattern to anunderlying surface. The imprintable medium may, for instance, beprovided as a resist deposited on a substrate, such as a semiconductormaterial, to which the pattern defined by the template is to betransferred. Imprint lithography is thus essentially a moulding processon a micrometer or nanometer scale in which the topography of a templatedefines the patterns created on a substrate. Patterns may be layered aswith optical lithography processes so that in principle imprintlithography could be used for such applications as integrated circuitmanufacture.

The resolution of imprint lithography is limited only by the resolutionof the template fabrication process. For instance, imprint lithographyhas been used to produce features in the sub-50 nm range with goodresolution and line edge roughness. In addition, imprint processes maynot require the expensive optics, advanced illumination sources orspecialized resist materials typically required for optical lithographyprocesses.

SUMMARY

According to a first aspect of the invention, there is provided animprinting method, comprising contacting first and second spaced targetregions of an imprintable medium on a substrate with first and secondtemplates respectively to form respective first and second imprints inthe medium, and separating the first and second templates from theimprinted medium.

In this way, it may possible to imprint a significant area of thesubstrate in a short time, which may improve the throughput of animprint lithography system.

In an embodiment, the method comprises, after separating the first andsecond templates from the imprinted medium, displacing the firsttemplate in a first direction from the first region to a third region ofthe medium and displacing the second template in a second direction fromthe second region to a fourth region of the medium, and contacting thethird and fourth target regions with the first and second templatesrespectively to form respective third and fourth imprints in the medium.

Thus, each template may be used to imprint a plurality of spaced regionsof the imprintable medium.

The first direction may take any desirable orientation in relation tothe second direction. For example, the first direction may be angularlyoffset from the second direction by any appropriate angle to enable thevarious regions of the imprintable medium to be imprinted in the optimalmanner for a given imprint system. In an embodiment, the first directionis substantially parallel to the second direction.

While the imprintable medium may be provided as a single large volume onthe substrate and the various regions to be imprinted form parts of thatsingle volume, in an embodiment, separate third and fourth volumes ofthe imprintable medium may be provided on the substrate to provide thethird and fourth spaced target regions. Moreover, separate first andsecond volumes of the imprintable medium may be provided on thesubstrate to provide the first and second spaced target regions.

In an embodiment, the first and second templates contact the mediumsimultaneously, alternatively, the first and second templates maycontact the medium sequentially. When contacting the mediumsequentially, the timing between each sequential contacting step may bemonitored and/or controlled to provide an optimum process to imprint aparticular substrate with a particular pattern.

According to an aspect of the invention, there is provided a method forpatterning a substrate, comprising:

contacting first and second spaced target regions of an imprintablemedium on a substrate with first and second templates respectively toform respective first and second imprints in the medium, each imprintcomprising a pattern feature and an area of reduced thickness.

separating the first and second templates from the imprinted medium;

etching the area of reduced thickness in the first and second targetregions to expose predefined areas of the substrate; and

etching the exposed predefined areas of the substrate.

Since multiple templates are employed, the rate at which a substrate ispatterned may be increased relative to conventional methods employing asingle template.

In an embodiment, the method comprises, after separating the templatesfrom the imprinted medium and before etching the areas of reducedthickness, displacing the first template in a first direction from thefirst region to a third region of the medium and displacing the secondtemplate in a second direction from the second region to a fourth regionof the medium, and contacting the third and fourth target regions withthe first and second templates respectively to form respective third andfourth imprints in the medium, each imprint comprising a pattern featureand an area of reduced thickness.

According to an aspect of the invention, there is provided an imprintingapparatus, comprising:

substrate table configured to hold a substrate; and

a template support configured to support first and second templates, thetemplate support configured to cause the first and second templates tocontact first and second spaced target regions respectively of animprintable medium on the substrate to form respective first and secondimprints in the medium and to cause the first and second templates toseparate from the imprinted medium.

In this way, the imprinting apparatus may imprint a significant area ofthe substrate in a short time, which may improve the throughput of animprint lithography system.

In an embodiment, the apparatus may comprise a dispenser configured toprovide a volume of an imprintable medium on a substrate supported onthe substrate table.

In an embodiment, the template support is operable such that, afterseparating the first and second templates from the first and secondregions of the imprinted medium, the first template is displaced in afirst direction from the first region to a third region of the mediumand the second template is displaced in a second direction from thesecond region to a fourth region of the medium, and the template supportis operable to cause the third and fourth target regions to be contactedwith the first and second templates respectively to form respectivethird and fourth imprints in the medium.

The apparatus and method of the present invention may be suitable forapplication in a drop on demand process (e.g., SFIL). Accordingly, in anembodiment, the method and/or apparatus may be provided to enable thisprocess.

Appropriately, there may be provided a dispenser configured to provideseparate third and fourth volumes of an imprintable medium on asubstrate to provide the third and fourth spaced target regions.Additionally, a dispenser configured to provide separate first andsecond volumes of an imprintable medium on a substrate to provide thefirst and second spaced target regions may be provided.

In an embodiment, the dispenser configured to provide the first andsecond volumes of the imprintable medium comprises a first dispenserconfigured to provide the first volume of the imprintable medium and asecond dispenser configured to provide the second volume of theimprintable medium.

In an embodiment, the first and second dispensers are associated withthe first and second templates respectively. The first and seconddispensers may be fixed relative to the first and second templatesrespectively, or may be moveable independently of the first and secondtemplates.

While the first direction may take any desirable orientation in relationto the second direction, in an embodiment, the first direction issubstantially parallel to the second direction.

The template support may be operable so that the first and secondtemplates contact the first and second regions of the mediumsimultaneously, alternatively, the template support may be operable sothat the first and second templates contact the first and second regionsof the medium sequentially.

Appropriately, the template support may be configured so that the firsttemplate is fixed relative to the second template. Alternatively, thetemplate support may be configured so that the first template ismoveable relative to the second template.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of exampleonly, with reference to the accompanying schematic drawings in whichcorresponding reference symbols indicate corresponding parts, and inwhich:

FIGS. 1 a-1 c illustrate examples of conventional soft, hot and UVlithography process respectively;

FIG. 2 illustrates a two step etching process employed when hot and UVimprint lithography is used to pattern a resist layer;

FIG. 3 illustrates relative dimensions of template features compared tothe thickness of a typical imprintable resist layer deposited on asubstrate;

FIG. 4 illustrates a multi-stamp printing arrangement in accordance withan embodiment of the present invention; and

FIG. 5 illustrates an alternative multi-stamp printing arrangement inaccordance with an embodiment of the present invention in which theimprintable medium is provided by drop on demand.

DETAILED DESCRIPTION

There are two principal approaches to imprint lithography which will betermed generally as hot imprint lithography and UV imprint lithography.There is also a third type of “printing” lithography known as softlithography. Examples of these are illustrated in FIGS. 1 ato 1 c.

FIG. 1 a schematically depicts the soft lithography process whichinvolves transferring a layer of molecules 11 (typically an ink such asa thiol) from a flexible template 10 (typically fabricated frompolydimethylsiloxane (PDMS)) onto a resist layer 13 which is supportedupon a substrate 12 and planarization and transfer layer 12′. Thetemplate 10 has a pattern of features on its surface, the molecularlayer being disposed upon the features. When the template is pressedagainst the resist layer, the layer of molecules 11 stick to the resist.Upon removal of the template from the resist, the layer of molecules 11stick to the resist, the residual layer of resist is etched such thatthe areas of the resist not covered by the transferred molecular layerare etched down to the substrate.

The template used in soft lithography may be easily deformed and maytherefore not be suited to high resolution applications, e.g. on ananometer scale, since the deformation of the template may adverselyaffect the imprinted pattern. Furthermore, when fabricating multiplelayer structures, in which the same region will be overlaid multipletimes, soft imprint lithography may not provide overlay accuracy on ananometer scale.

Hot imprint lithography (or hot embossing) is also known as nanoimprintlithography (NIL) when used on a nanometer scale. The process uses aharder template made from, for example, silicon or nickel, which aremore resistant to wear and deformation. This is described for instancein U.S. Pat. No. 6,482,742 and illustrated in FIG. 1 b. In a typical hotimprint process, a solid template 14 is imprinted into a thermosettingor a thermoplastic polymer resin 15, which has been cast on the surfaceof substrate. The resin may, for instance, be spin coated and baked ontothe substrate surface or more typically (as in the example illustrated)onto a planarization and transfer layer 12′. It should be understoodthat the term “hard” when describing an imprint template includesmaterials which may generally be considered between “hard” and “soft”materials, such as for example “hard” rubber. The suitability of aparticular material for use as an imprint template is determined by itsapplication requirements.

When a then setting polymer resin is used, the resin is heated to atemperature such that, upon contact with the template, the resin issufficiently flowable to flow into the pattern features defined on thetemplate. The temperature of the resin is then increased to thermallycure (e.g. crosslink) the resin so that it solidifies and irreversiblyadopts the desired pattern. The template may then be removed and thepatterned resin cooled.

Examples of thermoplastic polymer resins used in hot imprint lithographyprocesses are poly (methyl methacrylate), polystyrene, poly (benzylmethacrylate) or poly (cyclohexyl methacrylate). The thermoplastic resinis heated so that it is in a freely flowable state immediately prior toimprinting with the template. It is typically necessary to heatthennoplastic resin to a temperature considerably above the glasstransition temperature of the resin. The template is pressed into theflowable resin and sufficient pressure is applied to ensure the resinflows into all the pattern features defined on the template. The resinis then cooled to below its glass transition temperature with thetemplate in place whereupon the resin irreversibly adopts the desiredpattern. The pattern will consist of the features in relief from aresidual layer of the resin which may then be removed by an appropriateetch process to leave only the pattern features.

Upon removal of the template from the solidified resin, a two-stepetching process is typically performed as illustrated in FIGS. 2 a to 2c. The substrate 20 has a planarization and transfer layer 21immediately upon it, as shown in FIG. 2 a. The purpose of theplanarization and transfer layer is twofold. It acts to provide asurface substantially parallel to that of the template, which helpsensure that the contact between the template and the resin is parallel,and also to improve the aspect ratio of the printed features, as will bedescribed below.

After the template has been removed, a residual layer 22 of thesolidified resin is left on the planarization and transfer layer 21,shaped in the desired pattern. The first etch is isotropic and removesparts of the residual layer 22, resulting in a poor aspect ratio offeatures where L1 is the height of the features 23, as shown in FIG. 2b. The second etch is anisotropic (or selective) and improves the aspectratio. The anisotropic etch removes those parts of the planarization andtransfer layer 21 which are not covered by the solidified resin,increasing the aspect ratio of the features 23 to (L2/D), as shown inFIG. 2 c. The resulting polymer thickness contrast left on the substrateafter etching can be used as for instance a mask for dry etching if theimprinted polymer is sufficiently resistant, for instance as a step in alift-off process.

Hot imprint lithography suffers from a disadvantage in that not onlymust the pattern transfer be performed at a higher temperature, but alsorelatively large temperature differentials might be required in order toensure the resin is adequately solidified before the template isremoved. Temperature differentials between 35 and 100° C. may be needed.Differential thermal expansion between, for instance, the substrate andtemplate may then lead to distortion in the transferred pattern. Thismay be exacerbated by the relatively high pressure required for theimprinting step, due the viscous nature of the imprintable material,which can induce mechanical deformation in the substrate, againdistorting the pattern.

UV imprint lithography, on the other hand, does not involve such hightemperatures and temperature changes nor does it require such viscousimprintable materials. Rather, UV imprint lithography involves the useof a partially or wholly transparent template and a UV-curable liquid,typically a monomer such as an acrylate or methacrylatee. In general,any photopolymerisable material could be used, such as a mixture ofmonomers and an initiator. The curable liquid may also, for instance,include a dimethyl siloxane derivative. Such materials are less viscousthan the thermosetting and thermoplastic resins used in hot imprintlithography and consequently move much faster to fill template patternfeatures. Low temperature and low pressure operation also favors higherthroughput capabilities.

An example of a UV imprint process is illustrated in FIG. 1 c. A quartztemplate 16 is applied to a UV curable resin 17 in a similar manner tothe process of FIG. 1 b. Instead of raising the temperature as in hotembossing employing thermosetting resins, or temperature cycling whenusing thermoplastic resins, UV radiation is applied to the resin throughthe quartz template in order to polymerise and thus cure it. Uponremoval of the template, the remaining steps of etching the residuallayer of resist are the same or similar as for the hot embossing processdescribed above. The UV curable resins typically used have a much lowerviscosity than typical thermoplastic resins so that lower imprintpressures can be used. Reduced physical deformation due to the lowerpressures, together with reduced deformation due to high temperaturesand temperature changes, makes UV imprint lithography suited toapplications requiring high overlay accuracy. In addition, thetransparent nature of UV imprint templates can accommodate opticalalignment techniques simultaneously to the imprinting.

Although this type of imprint lithography mainly uses UV curablematerials, and is thus generically referred to as UV imprintlithography, other wavelengths of radiation may be used to cureappropriately selected materials (e.g. activate a polymerisation orcross linking reaction). In general, any radiation capable of initiatingsuch a chemical reaction may be used if an appropriate imprintablematerial is available. Alternative “activating radiation” may, forinstance, include visible light, infrared radiation, x-ray radiation andelectron beam radiation. In the general description above, and below,references to UV imprint lithography and use of UV radiation are notintended to exclude these and other activating radiation possibilities.

As an alternative to imprint systems using a planar template which ismaintained substantially parallel to the substrate surface, rollerimprint systems have been developed. Both hot and UV roller imprintsystems have been proposed in which the template is formed on a rollerbut otherwise the imprint process is very similar to imprinting using aplanar template. Unless the context requires otherwise, references to animprint template include references to a roller template.

There is a particular development of UV imprint technology known as stepand flash imprint lithography (SFIL) which may be used to pattern asubstrate in small steps in a similar manner to optical steppersconventionally used in IC manufacture. This involves printing smallareas of the substrate at a time by imprinting a template into a UVcurable resin, ‘flashing’ UV radiation through the template to cure theresin beneath the template, removing the template, stepping to anadjacent region of the substrate and repeating the operation. The smallfield size of such step and repeat processes may help reduce patterndistortions and CD variations so that SFIL may be particularly suited tomanufacture of IC and other devices requiring high overlay accuracy.

Although in principle the UV curable resin can be applied to the entiresubstrate surface, for instance by spin coating, this may be problematicdue to the volatile nature of UV curable resins.

One approach to addressing this problem is the so-called ‘drop ondemand’ process in which the resin is dispensed onto a target portion ofthe substrate in droplets immediately prior to imprinting with thetemplate. The liquid dispensing is controlled so that a predeterminedvolume of liquid is deposited on a particular target portion of thesubstrate. The liquid may be dispensed in a variety of patterns and thecombination of carefully controlling liquid volume and placement of thepattern can be employed to confine patterning to the target area.

Dispensing the resin on demand as mentioned is not a trivial matter. Thesize and spacing of the droplets are carefully controlled to ensurethere is sufficient resin to fill template features while at the sametime minimizing excess resin which can be rolled to an undesirably thickor uneven residual layer since as soon as neighboring drops touch theresin will have nowhere to flow.

Although reference is made above to depositing UV curable liquids onto asubstrate, the liquids could also be deposited on the template and ingeneral the same techniques and considerations will apply.

FIG. 3 illustrates the relative dimensions of the template, imprintablematerial (curable monomer, thermosetting resin, thermoplastic, etc.),and substrate. The ratio of the width of the substrate, D, to thethickness of the curable resin layer, t, is of the order of 10⁶. It willbe appreciated that, in order to avoid the features projecting from thetemplate damaging the substrate, the dimension t should be greater thanthe depth of the projecting features on the template.

The residual layer of imprintable material left after stamping is usefulin protecting the underlying substrate, but may also impact obtaininghigh resolution and/or overlay accuracy. The first ‘breakthrough’ etchis isotropic (non-selective) and will thus to some extent erode thefeatures imprinted as well as the residual layer. This may beexacerbated if the residual layer is overly thick and/or uneven.

This etching may, for instance, lead to a variation in the thickness offeatures ultimately formed on the underlying substrate (i.e. variationin the critical dimension). The uniformity of the thickness of a featurethat is etched in the transfer layer in the second anisotropic etch isdependant upon the aspect ratio and integrity of the shape of thefeature left in the resin. If the residual resin layer is uneven, thenthe non-selective first etch may leave some of these features with“rounded” tops so that they are not sufficiently well defined to ensuregood uniformity of feature thickness in the second and any subsequentetch process.

In principle, the above problem may be reduced by ensuring the residuallayer is as thin as possible but this may require application ofundesirably large pressures (possibly increasing substrate deformation)and relatively long imprinting times (perhaps reducing throughput).

As noted above, the resolution of the features on the template surfaceis a limiting factor on the attainable resolution of features printed onthe substrate. The templates used for hot and UV imprint lithography aregenerally formed in a two-stage process. Initially, the required patternis written using, for example, electron beam writing to give a highresolution pattern in resist. The resist pattern is then transferredinto a thin layer of chrome which forms the mask for the final,anisotropic etch step to transfer the pattern into the base material ofthe template. Other techniques such as for example ion-beam lithography,X-ray lithography, extreme UV lithography, epitaxial growth, thin filmdeposition, chemical etching, plasma etching, ion etching or ion millingcould be used. Generally, a technique capable of very high resolutionwill be desired as the template is effectively a 1× mask with theresolution of the transferred pattern being limited by the resolution ofthe pattern on the template.

The release characteristics of the template are also a consideration.The template may, for instance, be treated with a surface treatmentmaterial to form a thin release layer on the template having a lowsurface energy (a thin release layer may also be deposited on thesubstrate).

Another consideration in the development of imprint lithography is themechanical durability of the template. The template may be subjected tolarge forces during stamping of the imprintable medium, and in the caseof hot imprint lithography, it may also be subjected to high pressureand temperature. The force, pressure and/or temperature may causewearing of the template, and may adversely affect the shape of thepattern imprinted upon the substrate.

In hot imprint lithography, a potential advantage may be realized inusing a template of the same or similar material to the substrate to bepatterned in order to help reduce differential thermal expansion betweenthe two. In UV imprint lithography, the template is at least partiallytransparent to the activation radiation and accordingly quartz templatesare used.

Although specific reference may be made in this text to the use ofimprint lithography in the manufacture of ICs, it should be understoodthat imprint apparatus and methods described may have otherapplications, such as the manufacture of integrated optical systems,guidance and detection patterns for magnetic domain memories, hard diskmagnetic media, flat panel displays, thin-film magnetic heads, etc.

While in the description above particular reference has been made to theuse of imprint lithography to transfer a template pattern to a substratevia an imprintable resin effectively acting as a resist, in somecircumstances the imprintable material may itself be a functionalmaterial, for instance having a functionally such as conductivity,optical linear or non linear response, etc. For example, the functionalmaterial may form a conductive layer, a semiconductive layer, adielectric layer or a layer having another desirable mechanical,electrical or optical property. Some organic substances may also beappropriate functional materials. Such applications may be within thescope of one or more embodiments of the present invention.

An imprint lithography system may offer an advantage over opticallithography in terms of reduced feature width. However, the time takento stamp and cure the resin at each location on the substrate may limitthe throughput of an imprint lithography system and therefore a possibleeconomic advantage of adopting imprint lithography.

An embodiment of the present invention involves using a plurality oftemplates located on the same imprinting apparatus operating in parallelto each other, rather than using a single template on the apparatus.

FIG. 4 illustrates a portion 40 of a substrate area covered with animprintable medium. First and second templates 41, 42 are moved paralleland adjacent one another to imprint a pattern defined by the templates41, 42 respectively into the imprintable medium, which can then bereplicated in the substrate by one or more rounds of etching to removeresidual layers of imprintable medium remaining between pattern featuresafter imprinting and then etch exposed areas of the substrate underlyingthe residual layers.

In an embodiment, the templates are fixed relative to one another suchthat they always print regions having a fixed spatial separation.According to an alternative embodiment, the templates are free to moverelative to one another in order to better or optimally cover the areaof the surface to be printed. A refinement of this embodiment involvesat least one template having a smaller area than the other (or others).In such a system, the larger template(s) can imprint the main area ofthe substrate while the smaller template(s) can move around the edges ofthe printing area or between the gaps between the printed areas left bythe larger template(s).

The above embodiments may lend themselves for particular application todrop on demand processes (e.g., SFIL) in which the imprintable medium isapplied to the substrate as required, rather than being dispensed acrossthe entirety of the substrate prior to imprinting. Such an arrangementis illustrated in FIG. 5. A portion 50 of a substrate is being patternedusing first and second templates 51, 52 which are moving anti-paralleland adjacent one another. Each template 51, 52 has an associateddispenser 53, 54 configured to dose a volume of imprintable medium 55,56 immediately in front of the template 51, 52 (i.e., on a targetportion of the substrate to be next imprinted) on a drop on demandbasis. The drop on demand dispenser may, for instance, be mounted tomove with the respective template.

The throughput of the system may be improved or optimized by setting thetiming between resin dispersal and imprinting for each template suchthat imprinting occurs either in or out of synchronization. Animprovement in throughput of approximately 30-70% may be achieved for atwo template system by arranging the stamping and curing timesappropriately.

While specific embodiments of the invention have been described above,it will be appreciated that the invention may be practiced otherwisethan as described. The description is not intended to limit theinvention. For example, any number of templates having any appropriatesize and/or shape may be employed to suit a particular application.Furthermore, the speed at which the templates are moved around thesubstrate may be monitored and controlled to provide a good or optimalimprinting rate for a specific substrate size and pattern density.

1. An imprinting method, comprising: contacting first and second spacedtarget regions of an imprintable medium on a substrate with first andsecond templates respectively to form respective first and secondimprints in the medium; separating the first and second templates fromthe imprinted medium; after separating the first and second templatesfrom the imprinted medium, displacing the first template in a firstdirection from the first region to a third region of the medium anddisplacing the second template in a second direction from the secondregion to a fourth region of the medium; and contacting the third andfourth target regions with the first and second templates respectivelyto form respective third and fourth imprints in the medium.
 2. Themethod according to claim 1, comprising providing a volume of theimprintable medium on the substrate.
 3. The method according to claim 1,comprising providing separate first and second volumes of theimprintable medium on the substrate to provide the first and secondspaced target regions of the medium.
 4. The method according to claim 1,comprising providing separate third and fourth volumes of theimprintable medium on the substrate to provide the third and fourthspaced target regions of the medium.
 5. The method according to claim 1,wherein the first direction is substantially parallel to the seconddirection.
 6. The method according to claim 1, wherein the first andsecond templates contact the medium simultaneously.
 7. The methodaccording to claim 1, wherein the first and second templates contact themedium sequentially.
 8. The method according to claim 1, wherein eachimprint comprises a pattern feature and an area of reduced thickness andfurther comprising: etching the area of reduced thickness in the firstand second target regions to expose predefined areas of the substrate;and etching the exposed predefined areas of the substrate.
 9. The methodaccording to claim 8, comprising providing a volume of the imprintablemedium on the substrate.
 10. The method according to claim 8,comprising, after separating the templates from the imprinted medium andbefore etching the areas of reduced thickness, displacing the firsttemplate in a first direction from the first region to a third region ofthe medium and displacing the second template in a second direction fromthe second region to a fourth region of the medium, and contacting thethird and fourth target regions with the first and second templatesrespectively to form respective third and fourth imprints in the medium,each imprint comprising a pattern feature and an area of reducedthickness.
 11. An imprinting apparatus, comprising: a substrate tableconfigured to hold a substrate; and a template support configured tosupport first and second templates, the template support configured tocause the first and second templates to contact first and second spacedtarget regions respectively of an imprintable medium on the substrate toform respective first and second imprints in the medium and to cause thefirst and second templates to separate from the imprinted medium,wherein the template support is operable such that, after separating thefirst and second templates from the first and second regions of theimprinted medium, the first template is displaced in a first directionfrom the first region to a third region of the medium and the secondtemplate is displaced in a second direction from the second region to afourth region of the medium, and the template support is operable tocause the third and fourth target regions to be contacted with the firstand second templates respectively to form respective third and fourthimprints in the medium.
 12. The apparatus according to claim 11,comprising a dispenser configured to provide a volume of an imprintablemedium on a substrate supported on the substrate table.
 13. Theapparatus according to claim 11, comprising a dispenser configured toprovide separate first and second volumes of an imprintable medium on asubstrate to provide the first and second spaced target regions.
 14. Theapparatus according to claim 13, wherein the dispenser configured toprovide the first and second volumes of the imprintable medium comprisesa first dispenser configured to provide the first volume of theimprintable medium and a second dispenser configured to provide thesecond volume of the imprintable medium.
 15. The apparatus according toclaim 14, wherein the first and second dispensers are associated withthe first and second templates respectively.
 16. The apparatus accordingto claim 15, wherein the first and second dispensers are fixed relativeto the first and second templates respectively.
 17. The apparatusaccording to claim 11, comprising a dispenser configured to provideseparate third and fourth volumes of an imprintable medium on asubstrate to provide the third and fourth spaced target regions.
 18. Theapparatus according to claim 11, wherein the first direction issubstantially parallel to the second direction.
 19. The apparatusaccording to claim 11, wherein the template support is operable so thatthe first and second templates contact the first and second regions ofthe medium simultaneously.
 20. The apparatus according to claim 11,wherein the template support is operable so that the first and secondtemplates contact the first and second regions of the mediumsequentially.
 21. The apparatus according to claim 11, wherein thetemplate support is configured so that the first template is fixedrelative to the second template.
 22. The apparatus according to claim11, wherein the template support is configured so that the firsttemplate is moveable relative to the second template.
 23. An imprintingapparatus, comprising: a substrate table configured to hold a substrate;and a template support configured to support a plurality of templates,the template support configured to cause at least some of the templatesto contact a first set of target regions respectively of an imprintablemedium on the substrate to form a first set of respective imprints inthe medium, and to cause at least some of the templates to contact asecond set of target regions respectively of an imprintable medium onthe substrate, the second set of target regions displaced from the firstset of target regions, to form a second set of respective imprints inthe medium; and a dispenser configured to provide a volume of animprintable medium on the substrate, during or after the templatesupport causing the at least some of the templates to contact the firstset of target regions but before the template support causing the atleast some of the templates to contact the second set of target regions,to provide the second set of target regions.
 24. The apparatus accordingto claim 23, wherein the template support is configured to support atleast four templates.
 25. The apparatus according to claim 23, whereinthe template support is operable so that the templates contact therespective target regions of the medium simultaneously.
 26. Theapparatus according to claim 23, wherein the template support isoperable so that the templates contact the respective target regions ofthe medium sequentially.
 27. The apparatus according to claim 23,wherein the template support is configured so that a template of theplurality of templates is moveable relative to another template of theplurality of templates in a direction substantially parallel to a planeof the target regions.
 28. The apparatus according to claim 23, whereinthe dispenser comprises a first dispenser configured to provide a firstvolume of the imprintable medium and a second dispenser configured toprovide a second, separate volume of the imprintable medium.
 29. Theapparatus according to claim 28, wherein the first and second dispensersare associated with a first template and a second template respectivelyof the plurality of templates.
 30. The apparatus according to claim 28,wherein the first and second dispensers are fixed relative to a firsttemplate and a second template respectively of the plurality oftemplates.
 31. The apparatus according to claim 23, configured to directradiation through the at least some of the templates to cure the firstset of target regions before the template support causes the at leastsome of the templates to contact the second set of target regions. 32.An imprinting method, comprising: contacting each of a first set oftarget regions of an imprintable medium on a substrate with each of aplurality of templates respectively to form a first set of respectiveimprints in the medium; contacting each of a second set of targetregions of an imprintable medium on a substrate with each of a pluralityof templates respectively, the second set of target regions displacedfrom the first set of target regions, to form a second set of respectiveimprints in the medium; and providing a volume of an imprintable mediumon the substrate, during or after contacting the first set of targetregions but before contacting the second set of target regions, toprovide the second set of target regions.
 33. The method according toclaim 32, wherein the plurality of templates comprises at least fourtemplates.
 34. The method according to claim 32, wherein the pluralityof templates contact the medium simultaneously.
 35. The method accordingto claim 32, wherein the plurality of templates contact the mediumsequentially.
 36. The method according to claim 32, comprising moving atemplate of the plurality of templates relative to another template ofthe plurality of templates in a direction substantially parallel to aplane of the target regions.
 37. The method according to claim 32,comprising providing a first volume of the imprintable medium andproviding a second, separate volume of the imprintable medium.
 38. Themethod according to claim 37, wherein providing the first and secondvolumes are associated with a first template and a second templaterespectively of the plurality of templates.
 39. The method according toclaim 37, wherein providing the first and second volumes are at fixedlocation relative to a first template and a second template respectivelyof the plurality of templates.
 40. The method according to claim 32,further comprising directing radiation through the templates to cure thefirst set of target regions before the contacting the second set oftarget regions.